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Worksheets

MIDTERMS Tricarboxylic Acid Cycle

Total questions: 25

Worksheet time: 25mins

Name
Class
Date
1.

Which of the following is the first compound formed in the TCA cycle?

a)

Isocitrate

b)

Citrate

c)

Succinate

d)

Fumarate

2.

Which enzyme catalyzes the conversion of acetyl-CoA to citrate?

a)

Isocitrate dehydrogenase

b)

Alpha-ketoglutarate dehydrogenase

c)

Citrate synthase

d)

Aconitase

3.

Which intermediate of the TCA cycle is directly involved in substrate-level phosphorylation?

a)

Citrate

b)

Fumarate

c)

Succinyl-CoA

d)

Malate

4.

Which enzyme is responsible for the conversion of succinate to fumarate?

a)

Succinate dehydrogenase

b)

Fumarase

c)

Malate dehydrogenase

d)

Aconitase

5.

The final product of the TCA cycle that is regenerated at the end of the cycle is:

a)

Citrate

b)

Oxaloacetate

c)

Malate

d)

Acetyl-CoA

6.

Which of the following coenzymes is reduced during the conversion of isocitrate to alpha-ketoglutarate?

a)

NAD+

b)

FAD

c)

CoA

d)

ATP

7.

Which molecule is produced during the decarboxylation of alpha-ketoglutarate?

a)

ATP

b)

NADH

c)

CO₂

d)

FADH₂

8.

What is the final electron acceptor in the TCA cycle?

a)

Oxygen

b)

NAD+

c)

FAD

d)

Coenzyme Q

9.

Which of the following is NOT a product of the TCA cycle?

a)

NADH

b)

ATP

c)

FADH₂

d)

Oxygen

10.

What is the role of NADH and FADH₂ produced in the TCA cycle?

a)

They are converted into ATP via substrate-level phosphorylation.

b)

They carry electrons to the electron transport chain for ATP production.

c)

They act as intermediates in the synthesis of glucose.

d)

They regenerate oxaloacetate.

11.

Which molecule is involved in the reaction catalyzed by aconitase?

a)

Citric acid

b)

Aconitate

c)

Malate

d)

Isocitrate

12.

What happens during the reaction catalyzed by malate dehydrogenase in the TCA cycle?

a)

Malate is converted to fumarate

b)

Oxaloacetate is reduced to malate

c)

Malate is oxidized to oxaloacetate

d)

Fumarate is hydrated to form malate

13.

Which of the following intermediates in the TCA cycle is involved in the biosynthesis of amino acids?

a)

Citrate

b)

Alpha-ketoglutarate

c)

Fumarate

d)

Succinyl-CoA

14.

Which enzyme in the TCA cycle is regulated by ATP, NADH, and succinyl-CoA?

a)

Alpha-ketoglutarate dehydrogenase

b)

Citrate synthase

c)

Malate dehydrogenase

d)

Fumarase

15.

How many NADH molecules are produced per round of the TCA cycle?

a)

1

b)

2

c)

3

d)

4

16.

Which of the following enzymes catalyzes a reaction that produces FADH₂ in the TCA cycle?

a)

Alpha-ketoglutarate dehydrogenase

b)

Succinate dehydrogenase

c)

Citrate synthase

d)

Isocitrate dehydrogenase

17.

What is the role of Coenzyme A in the TCA cycle?

a)

It helps in the oxidation of acetyl-CoA.

b)

It carries electrons to the electron transport chain.

c)

It forms a bond with citrate.

d)

It assists in the decarboxylation of alpha-ketoglutarate.

18.

Which of the following molecules is produced during the conversion of succinyl-CoA to succinate?

a)

FADH₂

b)

ATP (or GTP)

c)

NADH

d)

CO₂

19.

Which step in the TCA cycle is involved in generating GTP or ATP?

a)

The conversion of succinate to fumarate

b)

The conversion of succinyl-CoA to succinate

c)

The conversion of isocitrate to alpha-ketoglutarate

d)

The regeneration of oxaloacetate from malate

20.

Which of the following is NOT a direct product of the TCA cycle?

a)

ATP

b)

NADH

c)

Pyruvate

d)

CO₂

21.

Describe the role of the TCA cycle in cellular respiration. Include its connection to other metabolic pathways like glycolysis and fatty acid oxidation.

4 lines
22.

Explain the process by which acetyl-CoA enters the TCA cycle. What are the key steps involved in the formation of citrate?

4 lines
23.

Discuss the importance of the enzyme citrate synthase in regulating the TCA cycle. How is it regulated?

4 lines
24.

Outline the steps of the TCA cycle where NADH is produced. How does NADH contribute to energy production in the cell?

4 lines
25.

Describe the role of FADH₂ in the TCA cycle. How is FADH₂ generated, and what role does it play in ATP production?

4 lines